Display Form Having Magnetically Attachable Parts

ABSTRACT

Forms for display of clothing and the like with magnetically attachable parts are provided. The magnetic joints comprise a magnetic assembly with a depth-of-pull sufficient to cause the attachable part to begin to pull toward the form at a distance preferably greater than one-half inch, preferably about one inch. Preferably the magnetic assembly has a depth-of-pull of at least about 120 gauss at a distance of one inch. A metallic plate is arranged in mating configuration with the magnetic assembly. Mating pins may be provided, as well as indexing pins. If the manikin is knocked over, or if the attached part is pulled or bumped, it will come loose rather than breaking off; and the mating parts are self-seeking in use, so that they will come together in proper orientation even when being mated beneath clothes. A bump to the manikin sufficient to overcome the on-contact strength of the magnetic attachment may not result in detachment of the limb because of the depth-of-pull strength of the magnetic assembly. The indexing pins allow the limbs to be placed in a variety of positions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/567,112 filed Dec. 5, 2006, which is a divisional of U.S. applicationSer. No. 10/797,624 filed Mar. 9, 2004, now U.S. Pat. No. 7,144,179,which is a continuation-in-part of U.S. application Ser. No. 09/771,431,filed Jan. 26, 2001, now U.S. Pat. No. 6,705,794, which claims priorityfrom U.S. provisional application No. 60/178,187, filed Jan. 26, 2000,all of which are incorporated herein by reference to the extent notinconsistent herewith.

BACKGROUND

Forms or manikins to display clothing or other merchandise are models ofcomplete human bodies or parts thereof, often of life-size proportions.It is difficult to dress such forms unless the limbs are detachable.

U.S. Pat. No. 3,028,058 discloses a manikin with truncated legs,swiveling arms, and a detachable head. In manikins with removable parts,at least one leg is often made to be removable, arms are removable, andthe torso may be made in two parts. Hands may also be detachable.Bayonet attachments are common means for attaching detachable limbs toforms, wherein a projection on the limb must be inserted into anappropriately shaped hole in the form, and turned for locking intoplace. U.S. Pat. No. 2,595,485 describes a fastener of this type, asdoes U.S. Pat. No. 2,081,071. There are numerous drawbacks to thismethod. The operation of attaching the removable piece must usually beperformed blind, i.e. under the clothing. Often, once the removablepiece is locked into position, it cannot be changed so as to place thelimbs in various expressive attitudes. Further, if the limb is bumped,it may be easily broken, or the entire form knocked over and damaged.

One attempt to solve these problems is described in U.S. Pat. No.5,727,717, which provides joints for manikins which use sandwich magnetsto keep the limbs in place. Male and female contours are used to providemating surfaces, and once the joint is in place, it does not rotate. Adrawback of this device is that the sandwich magnets do not providesufficient depth-of-pull to keep the limb from being easily knocked offby customers and store personnel by bumping when the form is in use. Ifthe limb is bumped with sufficient force to overcome the on-contactstrength of the magnet, the limb will simply fall off. Further, the limbmust be positioned with greater accuracy for attachment, since thesandwich magnet does not exert much force at a distance therefrom topull the limb into place when it has been placed approximately in thecorrect position. This device may allow limbs to be positioned in twopositions 180 degrees apart, but does not allow for positioning inattitudes between these extremes. Moreover, it is difficult to providesufficient strength with the sandwich magnets described in that patentfor secure attachment at small joints such as wrists and ankles, and theweight to strength ratio of such sandwich magnets is not good.

A lightweight means for attaching removable limbs to a form is neededwhich allows the limbs to be easily seated into place when the operatormoves them into approximate alignment, which holds with sufficient forcethat the limbs are not easily knocked off by being bumped, but whichdoes allow for detachment of the limbs when sufficient force is appliedwhich would otherwise knock over and damage the entire form.

All publications referred to herein are incorporated by reference to theextent not inconsistent herewith.

SUMMARY OF THE INVENTION

A form is provided which has a removable piece attached thereto by amagnetic system comprising a magnetic assembly having a depth-of-pullsufficient to cause the removable piece to seek home, i.e., begin tomove toward the attracted material, at a distance of at least one inchor, in other embodiments, a distance greater than one-half inch, e.g., adistance of about three-fourths inches. In one embodiment, this depth ofpull is about 120 gauss at one inch, more preferably it is greater thanabout 200 gauss at one inch and, most preferably, is about 240 gauss atone inch. Said magnetic assembly is positioned on said form or saidremovable piece. Said magnetic system also comprises an attractedmaterial on the other of said form or said removable piece so as to matewith said magnetic assembly.

A “form” is a manikin which may be in the shape of a human or animal, ora stylized human or animal. The removable piece may be any portion ofthe form, and is preferably selected from the group consisting of anarm, an upper arm, a lower arm, a hand, a leg, an upper leg, a lowerleg, a foot, a head, a torso, and a pelvis.

The attracted material may be steel, iron, or othermagnetically-adherent material known to the art, and is positioned onthe other of the removable piece or the main body of the form anddesigned to mate with a corresponding magnetic assembly. Magneticassemblies and attracted materials may also be placed on either or bothends of magnetic limbs, so that portions of limbs may be attached toeach other, e.g. hands to lower arms to upper arms. A given detachablepiece may comprise one or more structures made of attracted material,one or more magnetic assemblies, one of each, or any combination thereofas required to assemble the complete form.

The attracted material is preferably a piece of metal, preferably asteel disc having a thickness of at least about one-eighth inch. Athinner material will result in a less strong magnetic bond. Thickerpieces may be used, but will result in a heavier and more costly joint.

The depth-of-pull of the magnetic assembly is the amount of forceexerted by the magnetic material at a point a given distance from themagnetic assembly. In different embodiments, the magnetic assembly has adepth of pull of at least about 160 gauss or at least about 170 gauss ata distance of one inch. Preferably, the magnetic assembly has adepth-of-pull of at least about 200 gauss at one inch, and morepreferably a depth-of-pull of about 240 gauss at one inch. Thedepth-of-pull is preferably no greater than about 250 gauss at one inchto avoid pinching the operator=s fingers by having the magnetic assemblyengage with the attached material too quickly and strongly.

In addition to its depth-of-pull, the magnetic assembly will also havean on-contact strength, which is the amount of force required toseparate the magnetic assembly from direct contact with the attractedmaterial. Preferably, for joining an adult-size arm to a form, themagnetic assembly has an on-contact strength of at least about 60-120pounds, more preferably at least about 85 pounds, and most preferably,at least about 100 pounds. The on-contact strength is preferably nogreater than about 120 pounds. Preferably, for joining a child size armto a form, the magnetic assembly has an on-contact strength of at leastabout 20-60 pounds, more preferably at least about 30 pounds, and mostpreferably, at least about 35 pounds. For a shoulder cap, used to coverthe shoulder joint when no arm is required for the form, the on-contactstrength is preferably no more than about 20 pounds. The amount ofon-contact strength required should be sufficient to hold the limb inplace and prevent it from easily being knocked off during normal use andnot so great as to prevent manual disengagement of the limb by theoperator.

Appropriate on-contact strengths will be readily ascertainable by thoseof skill in the art, depending on the application. A discussion ofmagnetic properties and design is found at www.magnetsales.com.

While prior art magnetic limb attachments utilize magnets having goodon-contact strength, the need for good depth-of-pull has not previouslybeen recognized, and devices which provide good depth-of-pull have notbeen provided.

As used herein, depth-of-pull is defined in terms of gauss readings atvarious distances from the magnetic material measured in air, in theabsence of an attracted material.

A greater or lesser amount of magnetic material may be used in a largeror smaller magnetic assembly designed to fit infant wrist joints, adultarms, legs, heads, or other parts with differently-sized cross-sectionsto provide the required depth-of-pull. Preferably, the magnetic assemblyis arranged as described herein for the preferred embodiment, scaled upor down as appropriate. However, other materials and configurations maybe used, as will be appreciated by those skilled in the art.

The cup design is especially useful for adapting to various joint sizessince its on-contact strength can be varied, e.g., from around 0.5pounds up to 180 pounds with selection of appropriate magneticmaterials.

The magnetic material and configuration of the magnetic assembly toprovide appropriate on-contact strengths will be readily ascertainableby those skilled in the art without undue experimentation in accordancewith principles discussed herein and known to the art.

The manikins of this invention having magnetically attachable parts havethe following advantages: If the manikin is knocked over, or if someonepulls on the attached part, it will come loose rather than breaking off;and the mating parts are self-seeking in use, so that they will cometogether in proper orientation even when being mated beneath clothes.Generally, manikins are dressed with arms removed, and the arms thenhave to be inserted and positioned inside the sleeves ?blind,@ withoutthe dresser being able to see to align them properly. The self-seekingfeature of the magnetic mating parts of this invention substantiallyaids in ease of dressing and provides significant time savings formanikin dressers.

In a preferred embodiment hereof, a cup magnetic assembly comprising acircular cup which serves as a pole piece is provided. It is believedthat the cup shape focuses the magnetic energy toward the front (topedge of the cup), minimizing leakage of magnetic force. The cup need notbe circular; it can also be square, rectangular, oval, polygonal, orother shapes. A magnetic material within the cup provides the magneticforce. Many magnetic materials are known to the art including strontiumferrite ceramic magnets, neodymium and samarium cobalt. To optimizeperformance and cost, combinations of known magnetic materials may beused, e.g., combinations of lower power magnets such as strontiumferrite ceramic, ferrite with higher power magnets such as neodymium orstrontium cobalt, or either type with arnico or other medium powermagnet.

The cup assembly allows the magnetic field to be forced to the outeredges of the cup to take full advantage of the magnets being used.

A magnet seated within the cup, such as a ring magnet e.g. a ceramicmagnet such as a strontium ferrite ring having relatively lessdepth-of-pull, preferably not in contact with the sides of the cup, maybe used to provide on-contact strength for the magnet. As will beapparent to those skilled in the art, other types of magnetic materials,or combinations thereof, may also be used. The shape of the magneticmaterial may be varied; however, the magnetic material should not extendto the top of the cup, since if it is in direct contact with theattracted material, either some of the magnetic force will be lost orthe on-contact strength could be increased to unacceptable levels,depending on orientation of the poles of the magnetic material.Alternately, a non-magnetically adherent material can be used to preventdirect contact between the magnetic material and the attracted material(e.g. an austenitic stainless steel lid placed on the magnetic assemblyto cover the magnets), in which case the magnetic material need not bebelow the top of the cup. In an embodiment where the magnetic materialdoes not extend to the top of the cup involving a cup-shaped pole piecehaving a diameter of two and a half inches and a height of one-halfinch, there is a gap of about 0.15 inch between the magnetic materialand the top of the cup.

In order to provide more depth-of-pull, additional magnetic materialhaving a strong depth-of-pull in contact with the ring magnet, butseparated from direct contact with the pole piece (outer edges of thecup) may be provided. Because the size of the manikin joint is limited,the size of the magnetic assembly will be limited, and it will usuallybe necessary to conserve space within the cup-shaped pole piece. Usingnothing but strontium ferrite ceramic magnets in the preferredembodiment of this invention might require a pole piece too large to fitwithin the typical manikin joint. Thus, additional magnetic materials toprovide depth-of-pull are preferably made of materials which providegreater depth-of-pull than the ceramic magnets. Neodymium magnets arepreferred, e.g., neodymium-iron-boron materials. They may be in the formof a ring, radial arc segments, or any other desirable shape, so long asthe separation from the sides of the pole piece is maintained and thedesired depth-of-pull is achieved. In a preferred embodiment, themagnetic assembly comprises as additional magnetic material—twoneodymium arc segments symmetrically placed opposite each other, andspanning about 45-90 degrees of arc in the ring magnet. The size of suchadditional magnetic materials is selected to provide the requireddepth-of-pull as will be evident to those of skill in the art, or easilyascertainable without undue experimentation using the informationprovided herein. The additional magnetic materials are spaced apart fromthe pole piece (outer edges of the cup) a sufficient distance so thatthe magnetic force therefrom is not substantially conducted through thepole piece. Preferably, the additional magnetic materials are spacedapart from the pole piece at least about one-eighth inch in thepreferred embodiment hereof which involves the use of a circularcup-shaped pole piece having a height of one-half inch and a diameter oftwo and a half inches.

As will be readily apparent to those skilled in the art, the lessexpensive ceramic material can be entirely replaced with strongermagnetic material, and the size of the cup could be reduced accordingly;however, using a proportion of each type of material optimizes cost.

To facilitate embedding of the magnetic assembly, it preferablycomprises a flange attached thereto by welding or other means known tothe art which is covered by the material of the form as it is beingmolded or otherwise fabricated, leaving the remainder of the magneticassembly uncovered. The flange may comprise one or more pieces of metalor other material welded to the bottom of the cup assembly so that itextends on both sides, or single pieces of metal or other materialattached to the bottom of the cup so as to extend out on at least oneside.

The top of the magnetic assembly preferably defines a plane, and theattracted material preferably presents a planar surface for mating withthe magnetic assembly. A lid of metal, plastic or any other sheet-likematerial may be used to cover the magnetic assembly. If the lid contactsboth the cup pole piece and a magnet within the cup, the lid should notbe made of a magnetically adherent material. Non-magnetically adherentmaterials suitable for lids include nonmagnetic steels, where anonmagnetic steel is a steel which is not attracted by a permanentmagnet. Nonmagnetic steels include austenitic stainless steels. Othernon-magnetically adherent materials suitable for use as lids includealuminum, Mylar, plastics, glass, ceramics, and other materials as knownto those skilled in the art.

Preferably, the attracted material is in the form of a disc (circular orrounded plate) of steel or other magnetically attracted material. In anembodiment, the attracted material is in the form of an oval disc. Theattracted material may also have flanges or other projections therefromfor embedding in the material of the form.

The planar surfaces of the attracted material and top of the magneticassembly contact each other. Each of the magnetic assembly and attractedmaterial may be equipped with a mating pin or pins and an optionalindexing pin or pins, which mate with corresponding holes in the otherof the attracted material or magnetic assembly. In an embodiment, themating pin is centrally located, extending upward from the bottom of thecup magnet. Preferably it is rounded or chamfered to provide ease ofseating in the corresponding mating hole when it comes into contact withan edge thereof. The index pin or pins may be similarly rounded orchamfered. A plurality of index holes may be provided so that theremovable limb can be placed in different positions, e.g. an arm can beextended downward, outward or upward, a hand can be cupped or turnedover, and the like.

If desired, additional means can be provided to the magnetic system forproviding holding force in the direction of the magnetic attractionbetween the magnetic assembly and the attracted material. Suchadditional means can include Velcro strips, adhesive strips or othermaterials on the planar surfaces of the components or within the holesand pins, latches, or other means known to the art.

The magnetic assemblies and attracted materials may be sized toaccommodate the joints being attached. For example, smaller versionsmight be used at the wrists and ankles. The proportion of materialshaving a stronger magnetism to mass ratio could be increased to allowfor a stronger magnetic bond using the smaller size.

Methods for attaching removable pieces of forms are also provided hereincomprising aligning the pieces to be attached and allowing them to beheld in place by magnetic force, or placing the magnetic attachmentsystems in approximate alignment, and allowing magnetic force tocomplete the mating. Approximate alignment means that the components(the magnetic assembly and attracted material) are close enough togetherthat the strength of the magnetic field at that distance (thedepth-of-pull) is sufficient to pull the parts together. Specifically,the magnetic pull should be felt when the components are placed at leastabout one inch apart. It is often desirable that the distance betweenthe removable piece and the form be greater than about one-half inch,and preferably greater than about two-thirds or three-fourths of an inchwhen sufficient pull is present to allow the pieces to Aseek home.@Greater precision than these distances is difficult to achieve when theoperator is attempting to align the parts Ablind,@ i.e. under clothing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a form of this invention with removable and adjustablelimbs.

FIG. 1A shows a front view and FIG. 1B shows a side view.

FIG. 2 shows a portion of a cup magnet magnetic assembly of thisinvention. FIG. 2A is a top plan view, and FIG. 2B is a side view.

FIG. 3 shows a cup magnet magnetic assembly of this invention comprisingflanges, a mating pin and an index pin. FIG. 3A is a plan view and FIG.3B is a side view.

FIG. 4 shows a magnetic assembly of this invention mated with anattracted material.

FIG. 5 is a side view of a knee joint showing the metallic plate.

FIGS. 6A and 6B compare the lines of magnetic force in prior art formattachment magnet assemblies and the magnet assembly of this invention,showing how greater depth-of-pull is achieved in this invention.

FIGS. 7A and 7B show top and side views, respectively, of oval-shapedattracted material suitable for use with the magnetic assemblies of theinvention.

FIG. 8A is top view of a different cup magnetic assembly of theinvention, without a centrally located mating pin. FIG. 8B is a sideview of the magnetic cup assembly of FIG. 8A. FIGS. 8C and 8D,respectively show top and side views of a corresponding mating plate.

FIGS. 9A and 9B compare the depth-of-pull at the strongest points ofattraction for the magnetic assembly of the invention and a prior artsandwich magnet.

DETAILED DESCRIPTION

This invention provides manikins with magnetically attachable parts. Oneor more limbs selected from the group consisting of whole arms,forearms, upper arms, whole legs, thighs, lower legs, feet, hands, andhead, fingers, toes, and features may be magnetically attachable.Surrealistic features such as wings, chimeric animal parts, and the likemay also be magnetically attachable parts of this invention. Joint capssuch as shoulder caps may also be attachable. In a preferred embodiment,the whole arms are magnetically attachable.

The magnetic attachment comprises two mating portions: a materialcapable to adhering to a magnet, referred to herein as the ?attractedmaterial,@ such as steel, iron, or other magnetically-adherent materialknown to the art; and one or more magnets or magnetized materials,referred to herein as the ?magnetic material,@ selected and arranged toprovide a depth-of-pull sufficient for the attachable part to begin toseek home at a distance of about one inch, preferably at least about 120gauss at one inch. This arrangement of the selected magnetic material isreferred to herein as the magnetic assembly.

Magnetic materials may be selected to optimize cost and performance, asis standard in the industry. Table 1 lists several magnetic materials,comparing costs and coercive strengths. TABLE 1 Permanent MagnetMaterial Comparison Table Material Cost Index Coercivity Hci (KOe)Nd—Fe—B (sintered) 65% Up to 30 Nd—Fe—B (bonded) 50% Up to 11 Sm—Co(sintered) 100%  Up to 25 Sm—Co (bonded) 85% Up to 10 Alnico 30% Up to 2Hard Ferrite  5% Up to 3 Flexible  2% Up to 2Source: stanfordmagnets.com.

As will be appreciated by those of skill in the art, the placement ofmagnetic material with respect to pole pieces affects the flow andintensity of magnetic flux, and thus the strength of the magneticassembly both in terms of on-contact strength and depth-of-pull.Placement of air gaps between magnetic material and pole pieces alsoaffects performance. For example, in a cup magnetic assembly, if theceramic or neodymium components are allowed to touch the sides of thecup, some of the lines of force will be short-circuited through thesides and not reach past the rim of the cup and thus not be able to flowinto and hold the attracted material. However, magnetic material may bein contact with the sides of the cup if required to adjust the strengthof the magnetic assembly.

The magnets may be fixed in desired relationship to each other and thepole piece(s) by means known to the art, e.g., adhesives.

In an embodiment, the mating parts also include at least one mating pinprojecting from the face of one of the parts which fits into a holesized to accommodate it on the other part.

One or more index pins may also project from the face of one of theparts, and fit into holes sized to accommodate them on the other part.In this way, the limb can be adjusted to display a variety of positionsand postures.

Preferably the mating parts are in the form of substantially flat discswhich may be equipped with flanges for embedding in the material of theform. The attracted material may be a disc having a flat face formating, and the magnetic assembly preferably mates with this planarsurface. In a preferred embodiment, the magnetic assembly comprises acup construction made of a material such as steel, having magnetsarranged therein. Preferably the magnets do not extend outward past thetop of the “cup.”

The mating parts are preferably round, but may be any shape, such as thecross sectional shape of the limb being attached, rectangular, ovoid, orother shapes, including shapes having mating concavities and convexitiesto provide sockets, or cylinders which may be nested together.

The depth-of-pull strength of the magnetic assembly is also importantfor allowing the pieces to be joined to easily Aseek home,@ that is pullthemselves into proper alignment when they have been approximatelyaligned. Exact alignment is difficult for the operator to achieve whendressing a manikin, since the parts to be joined will often be obscuredby the clothing. The depth-of-pull strength should be sufficient for theparts to start moving together when they have been approximately alignedand are a distance of more than one-half inch apart, preferably adistance of one-third or more inches apart, more preferablythree-fourths or more inches apart and, most preferably, at least oneinch apart. The depth-of-pull should not be not so great as to causeinjury to the operator, nor so little as to require that the pieces beplaced in almost touching alignment, e.g. one-fourth inch apart, beforethey start to pull together.

Principles known to the art may be used to adjust the magnetic force,such as the thickness of the accepting material, the type of magneticmaterial used, and the mass of the magnetic material used.

Preferably, flanges extend outward from the mating parts so that themanikin body may be molded around them. Alternatively, the mating partscan be adhered to the manikin by any means known to the art includingscrews, welds, adhesives, and the like.

The manikin comprising the magnetically attachable parts is made of amaterial, preferably a molded polymeric material, capable of supportingthe mating parts. Manikins of this invention comprising magneticallyattachable parts may be replicas of normal human bodies, or may bemissing one or more parts, such as head, feet, lower legs, or otherparts enumerated above.

The attracted material may be on the manikin trunk or larger body part,and the magnetic material is on the smaller part to be attached, or viceversa. In one embodiment of this invention, manikins are equipped withmagnetic mating parts at some or all joints normally articulable in thehuman body.

FIG. 1A depicts a front view of a manikin of this invention equippedwith mating magnetic portions. In the drawings, like reference numbersindicate like drawing elements. The attracted material is a metallicplate 12 and the magnetic assembly 14 is mated thereto. Mating portionsare present between the head 10 and the neck 15, between the torso 20and the upper arms 22 at the shoulder joint 36, between the upper arms22 and the lower arms 24 at the elbow joints 26, between the lower arms24 and hands 30 at the wrists 28, between the torso 20 and pelvis 40,between the pelvis 40 and upper legs 50, between the upper legs 50 andlower legs 60 at the knee joints 54, and between the lower legs 60 andthe feet 62 at the ankle joint 64. A mating pin 18 and an indexing pin16 are shown in the magnetic assembly 14 of the left shoulder.

FIG. 1B shows a side view of a manikin of this invention showing ametallic plate 12 attached at the neck, at the shoulder 36, and elbow26, and indicating a variety of positions for the arm attainable usingindexing pins in the magnetic element (not shown) which fit intocorresponding indexing holes 34 shown in metallic plate 12 at theshoulder 36. This metallic plate 12 also shows mating hole 32.

FIG. 2A shows a magnetic assembly 14 of this invention consisting of apole piece 70 in the form of a cup. Inside the cup is a ring magnet 72in contact with the sides and bottom of the cup. Atop the ring magnetare two neodymium magnets 74 separated from the outer rim of the cup byspace 78. FIG. 2B is a side view of the magnetic assembly of FIG. 2A,showing that the ring magnet 72 underlies the neodymium magnets 74, andindicating that the neodymium magnets do not extend to the top of thecup.

In the preferred embodiment, the cup is a steel cup having a 2.5 inchdiameter weighing 114.5 g and about a 0.5 inch diameter hole in thecenter through which the mating pin extends. The ring magnet isstrontium ferrite and weighs 85.58 g. Two neodymium magnets weigh 17.9 geach. A stainless steel cover plate, not shown, weighs 12.5 g, themating pin weighs 16.4 g, the flange with the indexing pin weighs 28.0g, and the entire assembly weighs 293 g.

FIG. 3A shows the magnetic assembly equipped with flanges 76 forembedding the assembly in the material of the manikin, mating pin 18 formating with a corresponding mating hole in the attracted material(metallic plate), and indexing pin 16 on flange 76 for mating with acorresponding indexing hole in the metallic plate. FIG. 3B is a sideview of the magnetic assembly 14 of FIG. 3A, and shows the staked end 17of the indexing pin 16 and staked end 19 of mating pin 18.

FIG. 4 shows the magnetic assembly 14 and metallic plate 12 attached toa cup 13 equipped with a flange 77 for embedding within the material ofthe manikin. The mating pin 18 and indexing pin 16 extend into themetallic plate 12 when the magnetic system is in use, through matinghole 32 and indexing hole 34 provided therein. Magnetic assembly 14 isequipped with flange 76 for embedding it within the material of themanikin. The magnetic assembly 14 comprises pole piece 70, ring magnet72, neodymium magnets 74, mating pin 18, indexing pin 16, and lid 75.Mating pin 18 comprises a shoulder 21 to retain lid 75 in place.

In an embodiment, the metallic plate is included in a mating cup 13equipped with flanges 77 to provide appropriate recesses for the matingand indexing pins. Preferably, the plate has a diameter of 3.5 inches,and a hole having a diameter of about 0.5 inches in the center toaccommodate the mating pin. The mating plate may be embedded in thematerial of the form via the flanges, or it may be screwed or otherwiseattached to structures molded into the form for that purpose.

FIG. 5 shows a right side view of the knee joint 54 showing the metallicplate 12 in upper leg 50, with indexing holes 34 and mating hole 32.

FIG. 6A shows an end view of a prior art sandwich magnet consisting of aceramic magnet 82 and steel pole pieces 84. Lines of magnetic force 86indicate how the magnetic force runs from the magnet to the pole pieces,and across the top through the air between the pole pieces, as well asacross the bottom through the material of the manikin 88. This type ofmagnet design can provide good on-contact strength, but littledepth-of-pull. Magnetic poles are indicated as N and S.

In contrast, FIG. 6B shows a magnetic assembly 14 of this invention inwhich the lines of magnetic force 86 extend upward from the edge of polepiece 70 to provide a large depth-of-pull. Mating pin 18 and index pin16 are also shown in this view. Magnetic poles are indicated as N and S.

FIGS. 7A and 7B show top and side views, respectively, of an embodimentof an oval-shaped plate and flange assembly suitable for use with themagnetic assemblies of the invention. The central portion 100 acts asthe attracted material and as a mating plate for the magnetic assembly.Central portion 100 has side 103 connected to an outer portion 105. Whenthe assembly is attached to a manikin or a removable piece thereof, thecentral portion is elevated with respect to said outer portion. When thecentral portion is elevated with respect to the outer portion, thecentral portion projects further than the outer portion from the surfaceof the manikin or removable piece thereof where the joint is placed.Outer portion 105 acts as a flange which can then be embedded into themanikin or manikin piece. For example, the outer portion 105 may be usedto secure the plate to a polymeric form by covering the flange withliquid polymer during molding of the form. In addition, outer portion105 may contain additional features to further secure the mating plateto the form. FIG. 7B shows V-shaped depressions 107 made in the outerportion 105 and through-holes 109 formed in the vicinity of depressions107. In an embodiment, the through-holes 109 are formed where the outerportion 105 joins the side 103 of central portion 100. Although thedepressions in FIG. 7B are shown as V-shaped, other shapes ofdepressions known to those skilled in the art may be used.

V-shaped depressions 107 can help ensure that the plate and flangeassembly is correctly placed with the central portion 100 elevated withrespect to outer portion 105 when the assembly is molded into apolymeric form. To perform this function, the depressions in the outerportion 105 should be formed so that the assembly does not sit stably ona flat surface when resting on depressions 107. During molding of therelevant part of the polymeric form, the assembly can be held in placeby a flat portion of a mating magnetic piece which contacts centralportion 100. The magnetic mating piece used during molding is notrequired to be the same as the magnetic assembly which forms the otherside of the magnetic joint on the manikin. If outer portion 105 ratherthan the central portion 100 is inadvertently placed in contact with theflat portion of the mating magnetic piece prior to molding, the plateand flange assembly will not sit stably on the mating piece and themolding operator will be more likely to notice and correct the error.

During molding of a polymeric form, liquid polymer will flow throughholes 109, providing additional mechanical interlocking of the matingplate and the form when the liquid polymer solidifies. Preferably, theminimum dimension of holes 109 is about ⅛″ or greater. Preferably, themaximum dimension of holes 109 is about ½″ or less. Holes 109 arepreferably spaced apart from each other so as to distribute theadditional mechanical interlocking around the plate.

FIG. 7A shows mating hole 32 and index hole 34. Mating hole 32 is notrequired to be centrally located, as is shown in FIG. 7A. In anembodiment where the mating magnetic assembly is a circular cupassembly, the distance a shown in FIG. 7A can be substantially the sameas the radius of the circular cup. The outline of such a circular cup isshown by dashed lines in FIG. 7A.

The oval shaped device in FIGS. 7A and 7B may be formed from a metalstrip or coil by punching holes 32 and 34, using a half-shear operationto create a height difference between central portion 100 and outerportion 105, and further deforming outer portion 105 to create V-shapeddepressions 107, and separating the oval device from the strip or coil.Additional holes which partially define the oval and later aid inseparation of the oval from the strip or coil can be punched at the sametime as holes 32 and 34. For plate and flange assemblies made using thisprocess, the V-shaped depressions are preferably not placed along thecenter line connecting the mating and index holes to avoid deformingthese holes while forming the V-shaped depressions. The V-shapeddepressions can be formed deeply enough to tear holes 109 in the metal.In addition, a flattening operation can be used to restore planarity tocentral portion 100 after the die punching and half shear operation(s).Suitable steel coil thicknesses are between about 7 gauge and about 11gauge. Other processes as known to those skilled in the art, includingjoining two plates or a plate and a larger ring to create an innerportion 100 elevated relative to outer potion 105, may be used to createa plate and flange assembly similar to that shown in FIGS. 7A and 7B.

FIGS. 8A and 8B illustrate top and side views, respectively, of anotherembodiment of a magnetic assembly of the invention. The magneticassembly shown in FIGS. 8A and 8B does not contain a central mating pin,but rather two mating pins 18 placed outside the cup. The pins areattached to flange 76. FIG. 8B shows the staked ends 19 of the matingpins. The cup may be fuse-welded to the flange, or joined by other meansknown to those skilled in the art. FIG. 8C shows a top view of thecorresponding mating plate 12 showing mating holes 32. The mating plateis a flat circular disk with an attached strap 150. The strap may befuse-welded to the disk or joined by other means known to those skilledin the art. FIG. 8D shows a side view of the mating plate, illustratingstrap 150. The attached strap can be molded into a polymeric form or aremovable part thereof, thereby securing the mating plate to the form orremovable part thereof. Because the magnetic assembly shown in FIGS.8A-8B does not require a central mating pin, this design allows use of asmaller cup pole piece for a given magnet strength and magneticmaterial(s).

To make the devices of this invention, the components of the magneticassembly may be glued or soldered or otherwise adhered. The metallicplate and magnetic assembly are then embedded in the manikin, preferablyby molding the manikin around flanges or other projections thereof,however, these components may also be attached to the manikin by othermeans such as screws, adhesives, and the like, all as known to the art.

To use the magnetic joints of this invention, two parts areapproximately aligned, and the depth-of-pull strength of the magneticassembly then pulls the parts into place, with the mating pins andindexing pins in their corresponding holes. A plurality of indexingholes may be provided so that the limb can be placed in alternativepositions.

EXAMPLE 1

The on-contact and depth-of-pull strengths of magnetic assemblies ofthis invention were tested and compared to those of conventionalsandwich magnets using a gauss meter. FIGS. 9A and 9B show the pointswhere the measurements were taken. FIG. 9A shows the magnetic assemblyof this invention with the poles labeled N (north) and S (south). Theasterisk 90, positioned about one-fourth inch from the center of the2.5-inch-diameter magnetic assembly, indicates that the strongestdepth-of-pull force was measured at this distance from the center. Thecircle 92 on the perimeter of the pole piece 70 indicates that thestrongest on-contact force is measured at the perimeter. FIG. 9B shows asandwich magnet of the prior art. The asterisk 94 indicates where thestrongest depth-of-pull forces were measured. This point alsocorresponds to circle 96, the point where the strongest on-contactforces were measured. The magnet of this invention weighed 0.581 pounds.The sandwich magnet weighed 1.187 pounds. Results are shown in Table 2.TABLE 2 Two-pole Strontium Neodymium Cup Ferrite Sandwich Distance fromMagnet Assembly Assembly Strongest contact 2560 gauss 1410 gauss on PolePiece Strongest Point on 4021 gauss 1410 gauss Magnet 1/32 inch 3850gauss 1090 gauss ⅛ inch 2880 gauss 790 gauss ¼ inch 1890 gauss 510 gauss2 inch 850 gauss 270 gauss ¾ inch 380 gauss 160 gauss 1 inch 240 gauss110 gauss

These results show the superior depth-of-pull provided by the presentinvention. At ⅛ inch from the magnet, the force of the sandwich magnetbegins to drop off drastically, despite the fact that the sandwichmagnet weighs nearly twice as much as the magnetic assembly of thisinvention.

EXAMPLE 2

The on-contact and depth of pull strengths of a magnetic assembly asshown in FIGS. 8A and 8B were measured using a gauss meter, and areshown in Table 3. The strongest point on the magnet was measured at3/32″ (∀ about 1/32″) from the center of the magnet. The depth-of-pullforces were measured at this same location. This magnetic assembly beganto “seek home” at a distance of about ¾.″ The weight of the magnet wasabout 0.03 lb. TABLE 3 Neodymium Cup Distance from Magnet AssemblyStrongest contact 1500 gauss on Pole Piece Strongest Point on 2990 gaussMagnet 1/32 inch 2800 gauss ⅛ inch 2000 gauss ¼ inch 1550 gauss 2 inch680 gauss ¾ inch 338 gauss 1 inch 178 gauss

Although this invention has been illustrated using various specificcomponents, it will be appreciated by those skilled in the art thatalternative constructions and methods can be substituted for thosedescribed, and are equivalent thereto.

1. A manikin having a removable piece attached thereto by a magneticsystem comprising: (a) a magnetic assembly comprising a magneticmaterial and having a depth-of-pull sufficient to cause the removablepiece to begin to move towards the manikin at a distance from themanikin of more than one-quarter of an inch, said magnetic assemblybeing positioned on said manikin or said removable piece; (b) anattracted material positioned on the other of said manikin or saidremovable piece; comprising a strap for securing said attracted materialto the material of the manikin or removable piece on which it ispositioned;
 2. The manikin of claim 1 wherein the magnetic assembly hasa depth of pull of at least 160 gauss at a distance of one inch.
 3. Themanikin of claim 1 wherein the magnetic assembly has a depth of pull ofat least 170 gauss at a distance of at least one inch.
 4. The manikin ofclaim 1 wherein the magnetic assembly has a depth of pull of at least200 gauss at a distance of one inch.
 5. The manikin of claim 1 whereinsaid magnetic assembly is positioned on said removable piece.
 6. Themanikin of claim 1 wherein said magnetic assembly is positioned on saidmanikin.
 7. The manikin of claim 1 wherein said magnetic assemblycomprises a cup containing at least one magnet.
 8. The manikin of claim7 wherein said cup serves as a pole piece.
 9. The manikin of claim 7wherein said cup is a circular cup.
 10. The manikin of claim 1 whereinsaid magnetic system comprises a mating pin on one of said magneticassembly or attracted material, and a mating hole positioned to matewith said mating pin on the other of said magnetic assembly or saidattracted material.
 11. The manikin of claim 10 wherein said mating pinis located in the center of said magnetic assembly and said mating holeis located in the center of said attracted material.
 12. The manikin ofclaim 1 wherein said attracted material presents a circular face. 13.The manikin of claim 1 wherein said attracted material presents an ovalface.
 14. The manikin of claim 1 wherein said magnetic system furthercomprises at least one index pin on one of said magnetic assembly orsaid attracted material, and an index hole positioned to mate with saidindex pin on the other of said magnetic assembly or said attractedmaterial.
 15. A manikin having a removable piece attached thereto by amagnetic system comprising: (a) a magnetic assembly having adepth-of-pull sufficient to cause the removable piece to begin to movetowards the manikin at a distance from the manikin of more thanone-quarter of an inch, said magnetic assembly being positioned on saidmanikin or said removable piece; said magnetic assembly being a cupmagnetic assembly comprising a cup serving as a pole piece, said cuphaving at least one magnet therein; and (b) an attracted materialpositioned on the other of said manikin or said removable piece so as tomate with said magnetic assembly; (c) a mating pin on said magneticassembly or said attracted material, and a mating hole positioned tomate with said mating pin on the other of said magnetic assembly or saidattracted material; and (d) indexing means on one of said manikin orsaid removable piece for adjusting said removable piece to display avariety of positions and postures.